The catalog pg_description stores optional descriptions (comments) for each database object. Descriptions can be manipulated with the COMMENT command and viewed with psql's \d commands. Descriptions of many built-in system objects are provided in the initial contents of pg_description.
See also pg_shdescription, which performs a similar function for descriptions involving objects that are shared across a database cluster.
Table 43-17. pg_description Columns
|any OID column
|The OID of the object this description pertains to
|The OID of the system catalog this object appears in
|For a comment on a table column, this is the column number (the objoid and classoid refer to the table itself). For all other object types, this column is zero
|Arbitrary text that serves as the description of this object